A malocclusion is a misalignment of teeth or incorrect relation between the teeth of the two dental arches. According to Edward Angle, “father of modern orthodontics,” the mesiobuccal cusp of the upper first molar should align with the buccal groove of the mandibular first molar. The teeth should all fit on a line of occlusion, which is a smooth curve through the central fossae and cingulum of the upper canines, and through the buccal cusp and incisal edges of the mandible. Any variations therefrom are a malocclusion.
Orthodontics, formerly orthodontia (from Greek orthos “straight or proper or perfect”; and odous “tooth”), is the specialty concerned with the study and treatment of malocclusion, which can be a result of tooth irregularity, disproportionate facial skeleton relationship, or both. Orthodontics treats malocclusion through the displacement of teeth via bony remodeling and control and modification of facial growth. Simply put, pressure is applied to teeth, and the high pressure side results in bone loss (osteoclastic activity), whereas the low pressure side produces bone growth (osteoblastic). The socket holding the tooth thus gradually shifts position, moving the tooth along with it.
This process has been accomplished for hundreds of years using static mechanical force to induce bone remodeling, thereby enabling teeth to move. In modern orthodontics, braces consisting of an archwire interfaces with brackets that are affixed to each tooth. As the teeth respond to the pressure applied via the archwire by shifting their positions, the wires are again tightened to apply additional pressure. This widely accepted approach to treating malocclusion takes about twenty-four months on average to complete, and is used to treat a number of different classifications of clinical malocclusion.
Treatment with braces is complicated by the fact that it is uncomfortable and/or painful for patients, and the orthodontic appliances are perceived as unaesthetic, all of which creates considerable resistance to use. Additionally, the 24-month treatment time is very long, and further reduces usage. In fact, some estimates provide that less than half of the patients who could benefit from such treatment elect to pursue orthodontics. However, until recently, no method was available to speed orthodontic remodeling since increasing force only increases tooth resorption, and is thus contraindicated.
Cyclic forces have been proposed to speed orthodontic remodeling, but Mao was probably the first to show faster bone growth under vibration in a rabbit model. The early Mao studies provided a basis for both possible efficacy and likely safety for using vibration in humans to assist orthodontic tooth movement, but the Mao studies used rabbit cranial clamp and suture closure experiments. Therefore, a device suitable for human clinical work still had to be developed and tested.
OrthoAccel Technologies Inc., invented the first commercially successful orthodontic vibrating device, as described in US2008227046 and related cases, designed to apply cyclic forces to the dentition for accelerated remodeling purposes. Both intra-oral and extraoral embodiments are described in US2008227046, each having processors to capture and transmit patient usage information, which is an important tool in ensuring compliance. The bite plate was specially designed to contact occlusal as well as facial and/or lingual surfaces of the dentition, and thus was more effective than any prior art devices in conveying vibrational forces to the teeth. Additionally, the device was slim, capable of hands free operation, lacked the bulky head gear of the prior art devices, and had optimized force and frequency for alveolar bone remodeling. Thus, its comfort level and compliance was also found to be high, with patients reporting that they liked the device, especially after the motor was redesigned to be quieter and smoother, as described in US2010055634 et seq. In fact, this device has been marketed as AcceleDent® in the United States, and several other countries and has achieved remarkable commercial success since its recent introduction. AcceleDent® represents the first successful clinical approach to accelerate orthodontic tooth movement by modulating bone biology in a non-invasive and non-pharmacological manner. The device was tested in clinical trials and shown to speed orthodontic remodeling as much as 50% (Kau 2010).
A common side effect of using braces is the appearance of white spot lesions, uncovered when the braces are finally removed. These unsightly spots are a unwelcome sight for any teenager or young adult who wore painful braces for two to four years to improve their smile, only to have their teeth marred by chalky white spots at the end.
The earliest sign of a new carious lesion is the appearance of a chalky white spot on the surface of the tooth, indicating an area of demineralization of enamel. This is referred to as a white spot lesion, an incipient carious lesion or a “microcavity”. The formation of white spot lesions or enamel demineralization around fixed orthodontic attachments is a common complication during and following fixed orthodontic treatment, and mars the result of a successfully completed case.
Demineralization is an almost inevitable side-effect associated with fixed orthodontic appliance treatment, especially when associated with poor oral hygiene. The acidic byproducts of the bacteria in plaque are responsible for the subsequent enamel demineralization and formation of white spot lesions. These can cause caries thereby leading to poor esthetics, patient dissatisfaction and legal complications. The formation of white spot lesions after completion of orthodontic therapy is discouraging to a specialty, one of whose goals is to improve aesthetics in the dento-facial region.
White spot lesions develop in association with brackets, bands, arch wires, ligatures and other orthodontic devices that complicate conventional oral hygiene measures, leading to prolonged plaque accumulation. This concern raises the need for assessing the saliva, oral hygiene status and caries rate before beginning of treatment and initiating preventive measures. Orthodontists must take up the active responsibility to educate patients about the importance of maintaining good dietary compliance and excellent oral hygiene regime.
Clinically, formation of white spots around orthodontic attachments can occur as early as 4 weeks into treatment and their prevalence among orthodontic patients ranges from 2% to 96%. The labio-gingival area of the lateral incisors is the most common site for white spot lesions and the maxillary posterior segments are the least common site, with males affected more in comparison with females. One clinical study found that a sharp increase in the number of white spot lesions occurred during the first 6 months of treatment that continued to rise at a slower rate to 12 months, thus in initial months of the treatment critical evaluation of oral hygiene is recommended.
A method of improving hygiene of braces is thus critically needed. One method would be to design a whole-mouth toothbrush, such that braces, teeth and gums can be simultaneously cleaned.
US20120260442 describes a whole-mouth electric toothbrush that is U-shaped and has a plurality of rotating bristle heads thereon. However, this device is complex and would be expensive to manufacture, and in addition, the bristles are not optimized for use with braces or other fixed orthodontic appliances. To date, no commercial embodiment of such a device is available, probably reflecting the complexity of driving a plurality of rotating heads at a distance from motor components.
U.S. Pat. No. 6,353,956 describes an ultrasonic whole-mouth toothbrush that has bristles on the bite tray contacting all occlusal and vertical teeth surfaces. Thus, the point of contact with the teeth is the relatively soft bristles and very little vibration will be conveyed to the teeth and underlying bone. Further, the frequency used therein was ultrasonic, which has not yet been demonstrated to have any accelerative effect on tooth movement.
A simpler, non-vibrational whole-mouth tooth brush has become recently available. The BLIZZIDENT is made by 3D scanning. The cost is quite high, but is expected to decrease as 3D scanning costs continue to decrease. However, this device is not made to clean fixed orthodontic appliances, and requires manual activation by e.g., chewing action, to move the bristles.
What is needed in the art is a method of improving oral health, circulation, hygiene of braces, and the like. A method or device that takes advantage of the existing vibrational driver would be particularly useful, as providing additional functionality for the already cleared FDA device. This application addresses some of those improvements.